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Plasma concentration of atazanavir (ATV) may be reduced when coadministered with tenofovir (TDF) or proton pump inhibitors. Boosting ATV exposure with ritonavir (r) may make it possible to overcome these drug interactions. However, jaundice and loss of the metabolic advantages of ATV are more frequent using ATV/r than ATV alone. Herein, we assessed whether therapeutic drug monitoring (TDM) could make it possible to identify the subset of patients in whom removal of ritonavir could be attempted without risk of suboptimal plasma ATV exposure and subsequent virological failure. A total of 56 patients with undetectable plasma HIV-RNA under a stable triple regimen containing ATV 300/100 mg qd were switched to ATV 400 mg qd. Plasma ATV concentrations were measured using a reliable high-performance liquid chromatography method. Median plasma ATV C(min) fell from 880 to 283 ng/ml (p = 0.03) after removal of ritonavir. While all patients on ATV/r showed ATV plasma concentrations within therapeutic values (IC(min) above 150 ng/ml) before switching, four patients (7%) fell below this threshold after switching to ATV 400 mg qd. However, only one of this group experienced virological failure at week 24 of follow-up. TDF was part of the antiretroviral regimen in all four cases. From a total of 29 (52%) patients on ATV/r showing grade 3-4 hyperbilirubinemia, only 7 (12%) remained on it upon switching to ATV 400 mg qd (p0.001). Patients with complete viral suppression under ATV/r 300/100 mg qd may benefit from switching to ATV 400 mg qd guided by TDM, which may make it possible to minimize adverse events without compromising antiviral efficacy in most cases.

BACKGROUND Tipranavir (TPV) and darunavir (DRV) are potent against protease inhibitor (PI)-resistant viruses. Efficacy of these compounds when confronting distinct HIV subtypes is not known. METHODS All clinical specimens from HIV-positive patients sent to our institution for drug resistance testing between 1999 and 2006 were analysed. The prevalence of TPV and DRV resistance mutations was assessed based on the latest International AIDS Society-USA panel list. Phenotypic susceptibility to DRV and TPV was examined in a subset of these samples using the PhenoSense assay. RESULTS A total of 1364 genotypes were analysed, including 1178 from individuals infected with clade B (285 drug naive) and 186 with non-B subtypes (137 drug naive). The mean number (+/-SD) of DRV resistance-associated mutations was higher in clade B than non-B (0.4 +/- 0.9 versus 0.06 +/- 0.3; P < 0.001), and more frequent among PI-experienced than drug-naive patients (0.6 +/- 1.02 versus 0.02 +/- 0.21; P < 0.001). In contrast, the mean number of TPV resistance-associated mutations was higher in non-B than B subtypes (2.7 +/- 1 versus 1.2 +/- 1.6; P < 0.001), regardless of PI experience. Susceptibility to TPV and DRV was examined in 29 drug-naive patients infected with non-B subtypes (1A, 3C, 2CRF01_AE, 9CRF02_AG, 1CRF12_BF, 3CRF14_BG, 3F and 7G). All showed susceptibility to DRV and 93% to TPV. Interestingly, two subtype F specimens showed reduced TPV susceptibility, with fold-changes of 2.7 and 2.1, respectively. CONCLUSIONS Non-B subtypes show a greater number of TPV resistance-associated mutations than B viruses, regardless of PI exposure. While HIV clade has no influence on DRV susceptibility, some F subtypes may show reduced TPV susceptibility.

The use of abacavir (ABC) may be associated with a hypersensitivity reaction (HSR) that requires discontinuation of the drug. The HLA-B*5701 allele has been linked to this HSR. Information on the strength of this association across distinct geographic regions and ethnicities is scarce. We tested HLA-B*5701 in 53 Spaniards infected with HIV who received ABC treatment. The presence of HLA-B5701 had strong positive and negative predictive values for ABC HSR, 92% and 63%, respectively.

Darunabir, formerly TMC114, is a new protease inhibitor (PI) under clinical development designed to be active against HIV strains resistant to currently available PI. The virological and immunological response to ritonavir-boosted darunabir was assessed in four heavily antiretroviral-experienced patients who had failed enfuvirtide and two or more previous ritonavir-boosted PI regimens, including tipranavir in one instance. All four patients reached undetectable plasma HIV-RNA levels within 8 weeks of therapy and experienced significant CD4 cell count gains.

Summary CD4+ regulatory T (Treg) cells have been involved in impaired immunity and persistence of viral infections. Herein, we report the level, phenotype and activation status of Treg cells in patients chronically infected with human immunodeficiency virus (HIV) and/or hepatitis C virus (HCV). Expression of CD25, CD45RA, CD27, CD127 and CD38 was assessed on these cells using polychromatic flow cytometry in 20 healthy controls, 20 HIV-monoinfected, 20 HCV-monoinfected and 31 HIV/HCV-co-infected patients. Treg cells were defined as CD4+forkhead box P3 (FoxP3)+. The percentage of Treg cells was increased significantly in HIV patients compared with controls. Moreover, there was a significant inverse correlation between CD4 counts and Treg cell levels. Fewer than 50% of Treg cells expressed CD25, with differences in terms of CD127 expression between CD25+ and CD25(–) Treg cells. CD4+Foxp3+ Treg cells displayed predominantly a central memory phenotype (CD45RA–CD27+), without differences between patients and healthy controls. Activated Treg cells were increased in HIV patients, particularly considering the central memory subset. In summary, HIV infection, but not HCV, induces an up-regulation of highly activated Treg cells, which increases in parallel with CD4 depletion. Hypothetically, this might contribute to the accelerated course of HCV-related liver disease in HIV-immunosuppressed patients.

The recent availability of non-invasive tools to measure liver fibrosis has allowed examination of its extent and determination of predictors in all patients with chronic hepatitis C virus (HCV) infection. On the other hand, most information on hepatic fibrosis in HCV/human immunodeficiency virus (HIV)-coinfected patients has been derived from liver biopsies taken before highly active antiretroviral therapy (HAART) was widely available. All consecutive HCV patients with elevated aminotransferases seen during the last 3 years were evaluated and liver fibrosis measured using transient elastography (FibroScan) and biochemical indexes. Patients were split according to their HIV serostatus. A total of 656 (69.6%) HCV-monoinfected and 287 (30.4%) HIV/HCV-coinfected patients were assessed. Mean CD4 count of coinfected patients was 493 cells/muL and 88% were under HAART (mean time, 4.2 +/- 2.4 years). Advanced liver fibrosis or cirrhosis was recognized in 39% of the coinfected and 18% of the monoinfected patients (P0.005). A good correlation was found between FibroScan) and biochemical indexes [AST to platelet ratio index (r = 0.405, P0.0001), FIB-4 (r = 0.393, P0.0001) and Forns (r = 0.407, P0.0001)], regardless of the HIV status. In the multivariate analysis, age45 years, body mass index (BMI)25 kg/m(2), and HIV infection were independently associated with advanced liver fibrosis or cirrhosis. HIV/HCV-coinfected patients have more advanced liver fibrosis than HCV-monoinfected patients despite the immunologic benefit of HAART.

Tipranavir (TPV) is a novel non-peptidic protease inhibitor (PI). It binds strongly and selectively to the HIV-1 protease, is orally administered twice daily, boosted with low doses of ritonavir, and shows a favourable resistance profile. In the two registrational trials, named RESIST 1 and 2, TPV/ritonavir 500/200 mg b.i.d., along with an optimised antiretroviral backbone, provided better virologic responses than controls receiving standard of care ritonavir-boosted PI-based regimens. A total of 21 mutations at 16 protease codons have been shown to impact on TPV susceptibility and response rates. The TPV mutation score includes L10V, I13V, K20M/R/V, L33F, E35G, M36I, K43T, M46L, I47V, I54A/M/V, Q58E, H69K, T74P, V82L/T, N83D and I84V. Viruses containing eight or more of these mutations are generally resistant to the drug. TPV use is associated with an excess of grade 3/4 liver enzyme elevations compared with other ritonavir-boosted PIs, and the potential for drug-drug interactions is relevant and must be considered when prescribing TPV.

Liver disease is frequently seen in HIV+ patients as a result of coinfection with hepatitis B (HBV) or C (HCV) viruses, alcohol abuse and/or exposure to hepatotoxic drugs. The aim of this study was to assess the prevalence of liver cirrhosis, its main causes and clinical presentation in HIV+ patients. Observational, cross-sectional, retrospective study of all HIV+ individuals followed at one reference HIV outpatient clinic in Madrid. Liver fibrosis was measured in all cases using transient elastometry (FibroScan). All 2168 HIV+ patients on regular follow-up (76% males, 46% injecting drug users) were successfully examined by FibroScan) between October 2004 and August 2006. Liver cirrhosis was recognized in 181 (overall prevalence, 8.3%), and the main aetiologies were HCV, 82.3%; HBV, 1.6%; dual HBV/HCV, 2.8%; and triple HBV/HCV/ hepatitis delta virus (HDV) infection, 6.6%. The prevalence of cirrhosis differed among patients with distinct chronic viral hepatitis: HCV, 19.2%; HBV, 6.1%; HBV/HCV, 41.7%; and HBV/HCV/HDV, 66.7%. In 12 patients with cirrhosis (6.7%), no definite aetiology was recognized. Overall, cirrhotics had lower mean CD4 counts than noncirrhotics (408 vs 528 cells/microL respectively; P = 0.02), despite similar proportion of subjects with undetectable viraemia on highly active antiretroviral therapy. Clinical manifestations of liver cirrhosis were: splenomegaly, 61.5%; oesophageal varices, 59.8%; ascites, 22.6%; encephalopathy, 12.1%; and variceal bleeding, 6.1%. Liver cirrhosis and hepatic decompensation events are relatively frequent in HIV+ individuals. Chronic HCV and alcohol abuse, but not chronic HBV, play a major role. Transient elastometry may allow the identification of a significant number of HIV+ individuals with asymptomatic liver cirrhosis.

Background Pegylated interferon (PEG-IFN) α2a and α2b differ in their pharmacokinetic properties, which might have an effect on their antiviral effects against hepatitis C virus (HCV). Differences between PEG-IFN-α molecules could be more pronounced in HIV-coinfected individuals, in whom response to HCV treatment is impaired. Methods All HCV–HIV-coinfected patients included in PRESCO and EXTENT trials recruited at one referral centre were retrospectively analysed. In both trials, ribavirin (RBV) 1,000–1,200 mg/day was prescribed together with standard doses of PEG-IFN-α2a or -α2b. The attainment of serum HCV RNA Results A total of 218 patients were examined, 138 on PEG-IFN-α2a and 80 on PEG-IFN-α2b. Baseline characteristics were comparable in both groups. Undetectable serum HCV RNA at weeks 4, 12 and 24 was more frequently attained using PEG-IFN-α2a than -α2b (45% versus 27% [ P=0.02]; 65% versus 45% [ P=0.01]; and 75% versus 55% [ P=0.01], respectively), regardless of HCV genotype. Plasma RBV levels did not differ between groups. In multivariate analysis, HCV genotypes 2/3 (odds ratio [OR] 12.5; 95% confidence interval [95% CI] 3.45–33.33; PConclusions The antiviral effect against HCV seems to be greater for PEG-IFN-α2a than -α2b in the HIV setting. A shorter half-life of PEG-IFN-α2b could explain this finding.